I'm still confused : is there a difference between enamelling,
pottery and PMC kilns?

The difference is mainly in the firing temperature, the maximum
temperature a kiln fires at, and whether there’s a timer or
programming for ramp and soak, etc. Enamelling only takes a few
minutes in the heated kiln at relatively low temperatures and you
judge the development by eye, not timing - the small muffle kilns are
perfect for this. At the other end, pottery/ceramics - it depends
what sort of clay body you’re using. Low fire and earthenware clays
fire at the low end, and stoneware and porcelain at the other, where
you need cone 6 temperatures and over, and need to be able to heat up
the kiln slowly over a period of time to the firing temperature,
hold/soak etc for glaze firing…

Each process has its own needs - I use my SC2 kiln (which has a
maximum temp of about 1060 C - or 1940 F) for glass fusing and
bisque-firing my ceramics (I use porcelain), also for firing lustres,
and for silver clay. I have a small muffle kiln, no temperature dial
or timer or anything (you judge temperature by the colour of the
interior), solely for enamelling. And I have a Paragon Caldera for
high firing and glaze firing my ceramics.

Thank you for your I’m still confused : is there a
difference between enamelling, pottery and PMC kilns? Linda,
pottery/ceramics kilns are normally top loaders (at least in the US).
This doesn’t work for enameling because you have to take the enamels
out on a trivet with a long fork. You’d get burned if you tried that
with the average ceramic kiln. Many PMC kilns that I’ve seen are
small, maybe 15 cm in diameter with a lid which lifts off. This type
can be used for enameling, but the height of the dome cover limits
how high your trivet holding the enamel piece can be. I’m not sure
from your post if you’ve done a lot of enameling but enamels need to
be applied to both sides of the metal and therefore you can’t just
fire your enamel on the kiln bottom surface.

Larger enameling kilns and also burnout kilns for casting will work
fine, they are front loaders with doors that are easy to open and
close for quick removal of the enamel after firing. These kilns also
have a pyrometer so that you can check the inside temperature. Those
are the basics of kilns. If you want more info, you can contact me
off list…I enamel, throw pots and cast.

There are top-loading kilns and front-loading; brick kilns and fiber
kilns. Pottery kilns usually will get to higher temps (I used to
fire to cone 10, or 2450 F in my top-loading, brick ceramic kiln,
7.5 cubic feet). But for our purposes here, the main difference is
in the way they are controlled. Ceramics typically must reach their
target temp, and you’re done, so the kilns are just programmable to
do that. An enamelling kiln needs to be able to hold a temp within a
fairly small margin, so they can usually do that, but they will be
shut off manually.

For glass and metal clay-- and now, even more true with BronzClay–
it is useful or even necessary to have a kiln in which you can
control the speed of heating (“ramp speed”) and the length of time it
stays at a particular temp (“hold”), then have it move on to a
different temp at another ramp then hold. A kiln that will fire in
several segments with different ramp speeds and hold times is not
needed for enamels or ceramics, but it will fire them just fine,
provided it will get up to the temp you need. A kiln designed for
ceramics, on the other hand, is very difficult to use for these other
purposes. As an aside, the studio where I teach has a big brick
burnout kiln that can be programmed with several segments, and is
really well insulated. It is so great! I can set it toramp up
BronzClay at 100 degrees per hour (necessary if there is thick
stuff), hold for 2 hours at 1100, then continue on to 1520 and hold 2
1/2 hours. I lock the door and go home. The next day, there’s my
stuff, still hot, but perfectly fired. I’m spoiled!

The differences in kilns will be the high temperature that they can
fire to and the interior dimensions. Pottery can sometimes require a
higher firing temp than enameling and Metal Clay requires (if you
are firing porcelain). I recommend a digital controller if you are
firing Metal Clay, it does make things much easier and your results
will be more consistent. For enamel, you need something that will
fire at 1450F - 1650F, for Metal Clay you need a kiln to fire from
1145F-1650F and for pottery you need 1000F-2300F. Most potters use
larger kilns than artists dealing with enamel or Metal Clay. Enamel
can use large or small kilns. Metal Clay tends to use very small
kiln sizes.

Sandra Graves made some good points regarding the different type
kilns. I’d like to add something that often gets overlooked.

When firing ceramics or metal clay one is in and out of the kiln
once to load and once to unload. With enameling the door must be
opened frequently while in use. For this reason an enamel kiln
usually has a side mounted door or one that lifts vertically.
Without this feature one would have to reach over a very hot
surface.